Magnetic switching device



Sqn.y 22, 1964 Filed Oct. 13, 1960 N. G. VOGL, JR

MAGNETIC SWITSJHING DEVICE OUTPUTS FIG. 3

BYv

4 Sheets-Sheet 1 mvENToR NORBERT 6. VOLj AGENT SCP- 22 1964 N. G. voGL, JR 3,150,269

MAGNETIC SIITCHING DEVICE Filed Oct. 13, 1960 l 4 Sheets-Sheet 2 v OUTPUTS Fla-4N FIG. 5

N. G. vom., JR

MAGNETIC swI'rcHING DEVICE sept; 2z, 1964 4 Sheets-Sheet 3 Filed Oct. 15. 1960- wSmSo ..5 E252 o@ S 4 Sheets-Sheet 4 N. G. VOGL, JR

MAGNETIC SWITCHING DEVICE Sept. 22, 1964 Filed oct. 1:5, 1960 Zad CORES TYPICAL INPUT TYPICAL OUTPUT POSITIVE SATURIITIUII I e coREs FI G. 9

CORES NEGATIVE SATURATIOII F IG. 8a

\ Il \:y

OUTPUTS Flash IIIPUT UIIIDIIIG I 'INPUT 3,150,269 MAGNETIC SWITCHING DEVICE Norbert G. Vogl, Jr., Wappingers Falls, N.`Y., assignor to International Business Machines Corporation, Y New York, NX., a corporation of New York Filed Oct. 13, 196i), Ser. No. 62,454 i 7 Claims. (Cl. 307-.-88)

The 'invention relates to.l switchingrdevices, and more particularly to: improved magnetic load sharing lswitches and a method of constructing the samen;` v

Switching devices capableof applying power, to any of a plurality of loadsiind many uses in-the electricalarts.

-One example'iof such use is inthe `control of a magnetic .causes -the'cores` at the intersections of these windingsto have their magnetic condition changed. Thus, a group of memorycores, corresponding tothe bits of adata word, may be selected by applying adr-ive pulsecoinciden- 'tally toa selected vrow and column winding. i

Selection of al row winding and ay column winding in such an array may be accomplished by a magneticswitch. One type of magnetic switch is the load sharing type, whichtconsists ofa plurality of magnetic cores having a plurality of windings inductivelycoupled thereto in accordance with a combinational code. One class of Athese load sharing switches is disclosed by G. Constantine in the IBM. Liournal of Research and Development, vol. 2 (July 1958), pp. d-211, entitled A Load Sharing Matrix Switc and in copending application, Serial No. 745,395, tiled iune 30, 1958, and assignedrto the assignee of the instant application. This class of,switches, `which will hereinafter be referred to Kas.Constantine switches,`are so designed that, to obtain 1r outputs, it is Vnecessarypto have at least 21n{1 wires passing `through eachV of the switchcores lt can be seen that, for even relatively small vaiues of n, the required number of wirespassing through va core could get prohibitively large. ltis more difficult and therefore more expensiveto thread` this, larger num- .ber of wires through a core andit is .often necessary to also use large diameter cores, increasing'thephysical dimensions of. the switch. Also, theintenturn 4capacitance of the unused windings combines with the inductance of ,the windings themselves to form -tanl circuits, giving rise to harmful oscillations or ringing l. t

Two classes of improved load sharing switchesthose disclosed by M. Marcus in an article entitled,v Doubling the Eiciency `of the Load Sharing MatriXSwitch, appearing in the IBM- Journal ofResearch and rDevelopment, Vol. 3, April 1959, pp. l94-196and in a cepending application tiled November 20,- 1958, having Serial ,No 775,279, which will hereinafter lne-referred to as .Marcus switches; andt'nose disclosed by R. `T.Chien in an article entitled, Orthogonal Matrices, ErrorCorrectf ing yCodes and LoadSharing Matrix Switches, appearing .in the IRE Transactions On Electronic Computers, vol.

EC-8, September 1959, p. 400, and, in more detail, in a copending application tiled August 10, 1960, having Serial No. 48,712 which will hereinafter be referred to as Chien switches, both of which are lassigned to the assignee of the present application-require, `at least (nel-2) windings per core to achieve an n output switch. A third class 3,150,269 Patented Sept. 22, 1 964 er' t ICC .2 of improved matrix switches-those disclosed y,by L. A. Russell, in Va copending applicationled June 9, 1960, having Serial No.35,051, whichV is assigned tothe assignee ofthe present application and will hereinafter bei referred to as Russell switches-requires exactlyl (1r-lf2) windings per core to achieve 'an nl output switch. At 0 It can be seen vthat all of thezabove mentioned improved matrix switches suler from the same limitation (al; :though to alessergextenw .as the Constantine switches, namely,l thatas the number Yof outputs from the switch increases, the number of windings-per-core `becomes extremely (large. As mentioned before, these addedwindings have the disadvantages of l increasing the physical dimensions of the switch, (2,)increasing the difficulty and therefore the overall cost of fabricating the s witch, `(3) giving rise to `a large number of undesired ringing circuits, (4t) placing a` practical limit on the number `of outputs which can be" derived from a sigle switch-,-and (5) imposing operational speed limitations on theswitch.

It is, therefore, an object of this invention to provide'.

`wound in accordance with an input combinational code; -fsuch as those disclosed in `the beforementioned applications of.l Constantine, Marcus and Chien or variations thereof. Selected combinations of the input windings are coincidentally energized to cause' a net uxchange'of predetermined magnitude in at least the elements of one of said groups of elements.` There are also a plurality of output windings, at least one output winding coupling all the elements fromeach of the groups of elementsin accordance withan output icombinational' code, suchas those mentioned above.4 The sense in-whichjthe individual output windings couple, the magnetic elements is such that voltages induced by the net iiux changes in the magnetic elements will cancel in all but one of the output windings and `will be additive in that output winding to generate an output4 voltage of predetermined` magnitude.

Switches constructed as above described I'are substantially noiseless. Ateachings of thisinvention may also be applied to provide switches which are not entirely noiseless, as'will appear Itshould be understood, however, that the later herein.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. l In the` drawings: v

FIG. 1 is aschematic drawing of ani8inputn4output `magnetic switch constructed in accordance with this inmagneticgswitch constructed in accordance with an alternative embodimentof this invention. u FIG, 3 is a schematic drawing of anS-input 6output magnetic switch constructed in accordance `with still another embodiment ofthis invention.`

FIG. 4 is a Aschematic drawing of a 16input llt-output magnetic switch constructed. by expanding the'switch shown in FIG. 3.

FIG. 5 is a schematic drawing of.,a 16-input 12-output magnetic switch constructed by expanding the switch PFIG. 8b is a diagrammatic*representation of the hystersis loop forthe individual cores shown in FIG. 8a.

FIG. 9 is a schematic drawing of a l6-input 10-output switch constructed in accordance with theteachings of this invention with only a representative sample of the input windings being included.

The input winding pattern for the Constantine switches (the switches Vdisclo'se'din the beforementioned Constantine application, Serial No. 745,395) are derived by expanding the basic matrix pattern i' where a column represents a magnetic element and a row represents` an input winding coupling the elements.

The 1 and 0 symbols indicate the sense of coupling ofV the input windings with the elements.V According tothe convention adopted herein, a l at the intersection of a row and a column indicates that a current oi predetermined polarity will drive the element (i.e., create magnetic flux therein) in a positive direction. A at the intersection of a row and column yindicates that current of the same predetermined polarity in the winding will drive the element in a negative direction. YFor input currents of the opposite polarity the converse will be true.,

These symbol conventions will have the same signicance when used in connection withV input winding patterns throughout this application.

Itl will be noted that the pattern shown above is the complete input winding pattern for a switch having two cores and two outputs. The'basic matrix pattern may be expanded to give the input winding pattern for higher order switches in accordance with the following matrix:

Basic matrix pattern Basic matrix pattern Basic matrix pattern l Complement of basic matrix pattern where the entire winding pattern for a lower order switch is substituted for the basic winding pattern in the above matrix to derive the next succeeding higher order switch. Following the rules outlined above, Vva Constantine switch having four cores and four outputs would have the wind- ,ing pattern: y v

With a switch having awinding pattern as derived above, there w1ll be, for'any combination of positive and negative currents on the input lines, a net ux change in one direction in only one of the magnetic elements and cancelling fluxv changes in the rest. The natureA of these winding patterns is also such that there will alwaysbe n magnetic elements in a switch and ninput windings,'where n is a positive integer which is equal to a power of 2. A single 'output winding is provided Vfor each element-there being, therefore, n outputs from the switch.

With the switch asV described above, each input winding must carry currents of both polarities. Since the drivers generally4 used with the Constantine switches Vare capable of supplying only positive signals,rit isdesirable to use a pair of input windings and a pair of unipolar drivers in place of each of the single windings represented above. The rst winding of each pair is provided in accordance with the pattern shown, and the second winding of each pair is provided in accordance with the complement of the pattern shown. Therefore, a Constantine switch having n outputs will have 2n input windings plus one output winding, or 211-1-1 windings per core. The Constantine switches display load sharing characteristics only at the input windings. 1

The Russell switches (those disclosed in copending application Serial No. 35,051) possess load sharing properties at only the output windings. The winding pattern for these load sharing output windings is generally the same as that disclosed for they input windings of the Constantine switches. .Each magnetic element of a Russell switch is coupled by two unipolar current carrying inputV windings, one for read out'and one for write in, and by all of the output lines. There will, therefore, be (nv-k2) windings-per-core for an n output Russell switch. Y

' The present invention recognizes the fact that, where a relatively large Anumber of outputs are desired, the number of windings-per-core for a given number off outputs can be substantially reducedby designing a switch which possesses load sharing properties at both its input and its output windings.

Referring now toV FIG. 1, there s shown a schematic diagram of an S-input 4output matrix switch designed in accordance with one embodiment of this invention. In this drawing, and in those to follow the following conventions will be used: (l) all input windings will be assumed to carry unipolar current flowing from the drivers 26 to reference line 28; (2) the magnetic elements, represented by toroids, will be driven in a positive direction by the application of current on an input winding which passes over the. left side of the toroid and under the right side, thus carrying current down (into the paper) through the core;` (3) the elements will be ydriven in the negative direction by the application of current to an input winding which passes under the left side of the toroid and over the right side, thus carrying current up (out of the paper) through the element; (4) a net change of magnetic ux in a magnetic element in the. positive direction will induce a negative output voltage in an Voutput winding which passes over the top of the toroid and under the bottom (i.e., a winding passing down into the paper) and will induce a positive output Voltage in an output winding which passes under the top of the toroid and over its bottom (i.e., a winding passing up,Y out of the paper). liux in a magnetic element in the negative, direction will have a converse eiect in the output windings. It is to be understood that, while in the drawing the magnetic elements are shown as toroidall magnetic cores, any suitably shaped magneticelement may be used. Moreover, asvdescribed with reference to FIG. 8, a magnetic elemen as the term `is used herein, may comprise more than one core.

In FIG. 1, input windingsV 10a and 12a couple magnetic elements 14 and 16 in accordance with the basic Constantine pattern. Windings 18a and 20a similarly couple magnetic elements 22 and 24. Associated with each of the input windings 10a, 12a, 18a and 20a is acomplementarily Wound input windings 10b, 12b, 18h and 2017, respectively. These windings Yare connected to be selectively energized by input drivers 26 and are connected through common line 28 to a source of negative potential 30. The input drivers may be, for example, a series of electronic or electro-mechanical switches, one for each input line, which may be selectively closed by an external control means to complete a circuit from ground through the selected input winding to B terminal 30. Each magnetic element of the two element Constantine type switches is coupled by two output windings, output windings 32 and 34 coupling elements 14 and 22, and output windings 36V and 38 coupling magnetic elements 16 and 24. vFor this A net change in embodiment, each output winding pair is shown as being connected in accordance with the basic Constantine pattern. One end of each output winding is connected through common line 40 to ground. The method of obtaining an output voltage from this circuit can best be understood by referring to a pair of examples.

(1) Assume that a negative (read-out) output voltage is desired on output winding 34. This would be accomplished by closing switches to energize input windings a, 12a, 1811 and 20b. The positive input signal on line 10a would induce ilux in elements 14 and 16, tending to drive these elements in a positive direction. The input current and to generate a flux in the element 16 which would tend to cancel that generated by the winding 10a. There would, therefore, `be a net flux change in the positive direction in the element 14 and no net flux change in the element 16.

The input windings 1811 and 20b induce fluxes in the elements 22 and 24, which are the complement of those induced in the elements 14 and 16 by the windings 10a and 12a respectively. A net flux change in the negative direction therefore occurs in the element 22 and no net llux change occurs in the element 24. The output Winding 32 passes over the top and under the bottom of both elements 14 and 22 and, therefore, has opposing voltages induced in it and no net output voltage. Output winding 34, however, passes over the top and under the bottom of element 14 but under the top and over the bottom of element 22; it, therefore, has a negative voltage induced in it by the next flux changes in each of these elements and a negative output voltage appears on this winding. Since no net flux change occurs in magnetic elements 16 and 24, no output signal is gener-ated on the output lines 36 and 38.

(2) Assume it is `desired to generate a positive (writein) output on the winding 34. In driving a memory, a write output always follows a read output on a given line. This is accomplished by energizing the complementarily Wound input windings 10b, 12b, 18a and 20a. windings 10b and 12b induce aiding negative fluxes in core 14, but they induce cancelling fluxes in core 16. Windings 18a and 20a induce aiding positive fluxes in core 22, but they induce cancelling uxes in core 24. The negative llux v ,change in core 14 induces positive voltages in windings 32 and 34. The positive flux change in core 22 induces a negative voltage in winding 32 and a positive voltage in winding 34. The positive voltages in winding 34 add to provide the desired output, while the opposed voltages in winding 32 cancel.

From the above description, it is apparent that when an input current is applied, most of the magnetic elements must be capable of being driven in either direction and therefore that these magnetic elements must have a zero or near zero remanent induction level (Le. must normally exist in an unsaturated state so as to be capable of being driven into either positive 'or negative saturation). The zero remanent induction level is the point at the intersection of the B and the H lines in FIGS. 7 and 8b. The other magnetic elements, namely those in the top row, need be capable of being driven only in one direction, but some means must be supplied for resetting these elements. In practice, a write-in 4current on a complementarily wound winding will follow each read-out current and these write-in currents will reset all the magnetic elements. If the write-in current is not available, the elements may be reset by a D.C. bias winding (for example as shown mentY as shown` inFIG. 8a consists of two magnetic cores,

A and B, each having the hysteresis loop shown in FIG. 8b and each of which is coupled in the same sense by an input winding 41 and an output winding 42. A bias winding 43 couples the 4cores A and B in opposite sense. With this arrangement, one of the cores, for example, the A core, is biased to'remain at a negative saturation level (point N on the hysteresis loop); While the other core, for example, the B core, is biased to remain at a positive saturation level (point P on the hysteresis loop). An input signal on an input line passing through both of the cores will induce no flux change in one of the cores but will induce the desired iiux change in the other core, this flux change, in turn, inducing the desired output voltage. At the end of the input signal, the switched core will be restored to its initial condition by the signal on the bias winding, or by the driver supplying a current of opposite polarity to input winding 41.

The switch shown in FIG. 1 is the lowest order switch having a Constantine winding pattern for both the input windings and the output windings. The number of outputs from this switch may be increased by increasing the number of magnetic elements in each row (by using a higher order Constantine input pattern), by increasing the number of magnetic elements in each column (by using a higher order Constantine output pattern), or by. a combination of these two procedures. The method of expanding the magnetic switches of this invention is generally the sarne for all embodiments and will, therefore, be described in detail after looking at the other embodiments.

The beforementioned copending application of Marcus discloses a matrix switch winding pattern which is somewhat more eicient than that disclosed by Constantine. This pattern is derived by starting with the basic winding pattern and expanding it in the following manner:

(1) Form two columns of the next higher order wind ing pattern for each column of the present order winding pattern by inserting the existing column values in the first 'three quadrants of a matrix `and inserting the complement of the existing column values in the fourth quadrant, thus Existing column values y Existing column values Existing column values Complement of existing The next higher order winding pattern will accordingly have one more than twice the number of columns in the existing pattern.

As an illustrative example, consider the manner of deriving the winding pattern for a three-core four-input switch.

' First,V the basic pattern is expanded by placing the column value of the basic pattern in the first three quadrants of a matrix and the complement of the column value for the basic pattern in the fourth quadrant, thus Then, in accordance with rule 2, the basic Winding pattern is expanded by adding the same value to each end so that the pattern for the iirst column becomes:

0 Now combining the first column found by rule 2 with Ythe two additional columns found by the rule 1, the winding pattern for the 3-core 4-input switch is 58, 5t), 62 and 64 couple the three cores 66, 68 and 70 in accordance with the saine winding pattern. As in FIG.

1, the input drive windings are connected to be selectively v Y energized by input drivers 26 and are connected by a common line 28 to a source of negative potential 30. Output windings '72 and 74 couple magnetic elements 52 and 66 in accordance with the beforementioned Constantine pattern; output windings 76 and 78 couple magnetic elements 54 and 68 and output windings, 80 and 82 couple magnetic elements 56 and 70 in accordance with the same winding pattern. Common line 40 connects one end of each of the output windings to ground.

The operation of this'circuit, which is similar to that ofthe circuit shown in FIG. 1, will be illustrated by the following example. Y

Assume that it is desired to obtain a negative output signal on'output'winding 76. This would be accomplished by applying positive drive signals to inputV windings 44, 48, 58 and 62. The positive going fluxes induced in the elements 52, 54 and 56 by the positive signal on input winding 44 would be cancelled in elements 52 and 56 by the negative going uxes induced by the positive current on winding 48 and would be augmented in magnetic element 54 by the positive going llux induced by winding 48. The positive currents on input windings 58 and 62 cause corresponding flux changes in magnetic elements 66, 68 and 70. The result is a net positive flux change in magnetic elements 54 and 68 and no net ux change in the other elements of the switch. The net positive ux change in the element 54 would induce negative voltages in output windings 76 and 78, while fthel positive going flux change in magnetic element 68 would induce a negative voltage output winding 76 and a positive voltage in output winding. 7S; the desired negative output voltage would, therefore, appear on winding 76.

The beforementioned copendng application of Chien discloses several'impnoved winding patterns for loading sharing magnetic switches, which, for large switches, are even more eicient than those of either Constantine or Marcus. Only one of the methods disclosed by Chien for deriving a winding pattern, that called Lemma 2 in the Chien application, will be described here and applied to the present invention; however, it is to be understood that a winding pattern derived by any of the methods disclosed in Chien may be used for the input windings in the present invention. The method of deriving a winding pattern employing Lemma 2 is described starting on page 23 of the copending Chien application and may be surnmarized as follows:

This method, which is applicable only Where n, the number of inputs, is a multiple of 4 and Where (1t-1) is a prime number p, consists of the following steps:

(l) List all numbers from 0 to (p-l iind all squares, and reduce these squares by multiples of p so that the resulting numbers are less than p. These numbers are called quadratic residues of p.

(2) Lay out in a column the sequence a0, al, a2, a3, a4, ap 1 and inserta l for a0 and Wherever the subscript is a quadratic residue and a 0 where the subscript is not a quadratic residue.

(3) Cyclically shift the sequence obtained in step 2 tjolobtain amatrix of p by p according to the sequence e ow:

i (4) Add a row of Os at the end of the matrix obtained 1n step 3 to obtain the linal matrix.

As an example, consider the construction of a 4input matrix: The prime number p is then 3. The first step, according to Lemma 2, is to iind all quadratic residues of numbers from 0 to (p-l);

Numners: Y 1 Quadratic residues 2 j 1 (2 2=4 and 4^-3=1) According to the next steps: (2) A column is laid .out-

a2 Substitutions made:

O (3.) The sequence is cyclically shifted- `(4) A row of zeros is added at the endrto p l-mput matrix patternas follows- 'As another example, consider theconstruction of an 8-1nput switch according to Lemma 2. The prime numform the quadratic residues would be computed as follows:

i VVVNext, the sequence is computed, `cyclically shifted, and

a row of zeros is added to give the following winding pattern:

Referring to FIG. 3, input windings 90, 9 2, 94 and 96 4couple magnetic elements 98, 100, and 192 in accordance with the four-input Chien pattern shown above.

Innut windings 104, 166, 108 and 11b couple magnetic elements 112, 114 and 116 in accordance with the same pattern. As before, the input windings are connected to be selectively energized by input drivers 26 and are connected through common line '28 to asource of negative potential 30. The six output windings 113428 are coupled in accordance with the same pattern as that vshown in FIG. 2 and, as in that embodiment, one end of each output winding is connected through a common line 40 to ground.

It should be noted that this switch and that shown in FIG.` 2 are structurally similar, differing only in the method used to derive the input `winding pattern. In operation these two circuits differ only in that different input windings are energized to obtain outputs on corresponding output windings. For example, to obtain a negative output voltage on output winding 122, input windings 92, 94, 166 and 108 would be energized.

While all the matrix switches of this invention give a substantial reduction in the number of windings-per-core for a given number of outputs, it has been found that the greatest reduction in number lof windings-per-core can v be obtained when the input windings are wound in accordance with the Chien pattern. The following detailed .description of the methods of increasing the number of outputs from the switches of this invention will therefore be given with reference to switches having Chien input patterns; howevenas mentionedbefore, the same geni eral method would be -applied to any of the embodiments mentioned so far.

FIG. 4 illustrates one method of increasing the number of outputsfrom a matrix switch embodying the principles o of this invention. The expansion is accomplished by substituting a higher order Chien input winding pattern for the one used before. In FIG. 3 tour input windings link three cores each in accordance with the 4input Chien pattern, whereas in FIG. 4, eight input windings link seven cores each in accordance with the S-input Chien pattern.

f To obtain an output on one of the output windings of the ,with a still higher order Chien input pattern.k For example, iftwo rows of magnetic elements, each having their linput windings wound in accordance with a 12-input Chien pattern were used, Va switch having twenty-two outputs could be obtained.

10 FIG. 5 illustrates a second method of increasing the number of outputs from a magnetic switch embodying the principles of this invention. Here, the same order Chien pattern is used for the input windings -as was used in FIG;

3, but la higher order Constantine pattern is used for the output windings and the number of rows of magnetic elements is, therefore, increased. As long as the output windings are wound in accordance with a Constantine pattern, it will be necessary to have sa number of rows of magnetic elements equal to an integral power of two. Following this method one step further, it can be seen that the number of outputs can be increased to twenty-four by using eight rows of magnetic elements, each wound in accordance with the 4input Chien pattern.

` A third method of increasing the number of outputs from a switch embodying the concepts of this invention would be to expand the switch in both directions by combining the two methods described above. It is tovbe noted that' the first method described aboveresults in greater load sharing at the input windings, whereas the second method described above results in greater load sharing at thev output windings; since it is generally desirable to maintain nearly equal load sharing at both the input and the output windings, the third method is the one generally employed when a large number of outputs is desired. In -all embodiments described so far, the input windings have been -arranged in sets, all the windings in each set passing through all the elements in a corresponding row of elements. It is not, however, necessary that the input windings be arranged in this manner. If, for example, the switch is to be used in a computing machine having its own standard code patterns, it would be desirable to design a switch embodying the concepts of this invention which utilized the machine standard code patterns. The input winding pattern for such a switch is shown'in diagrammatic form below:

Winding/Element wvhere the elements are arranged as shown in FIG. 9.

Ten output windings couple the elements of this embodiment in `accordance with the before described Constantine code. For the sake of clarity, only the output windings and a vrepresentative sample of the input windings are shown in FIG. 9. i

li duced in. all but one of the output windings must always be zero. Generally,-this wouldrequire that each output winding couple an even number of cores (although, there is a possibility that some code might be devised in' which *the output winding would always couple an odd numb/erV of cores havingzero net eXcitation).. The Constantine code is the only one considered so farV which has each winding coupling an` even number of magnetic. elements.

FIG. @shows graphically the tremendous reduction in Y lthe number of windings-per-core for ,aY given number of outputs `which is achieved by switches embodying the cnvcepts'of'this invention. The line marked Vogl is computed for switches constructedin .accordance withthe principles of this` invention whichhave Chien input winding patterns. This line is'compared with linescomputed induced in them and all other elements will have zero net ilux change. If for some reason outputs were Ydesired or permitted on two or more ofthe output windings, the above requirement would be modiiied accordingly.

l The only limitation on the output winding pattern is that it berone which will permit a net voltageto be induced in only one of the output windings by the net iluX changes in the magnetic elements caused byany desired combination of input signals.

put windings, the above requirement would lbe modiiied accordingly. Y r Y i While the invention has been particularly shown and described with referencel to preferred embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be` made therein without departing from the spirit and scope of the invention;

I claim:

Vl. A magnetic switch comprising a pluralityof magnetic elements at least some ofvwhich are stable only at a near Zero remanent induction level, said elements being arranged in groups of at least two elements each; a plurality of input windings each of which couples elements of more than one group and Vcouples only one elementV of each of said groups of elements in accordance with an input combinational code; means for coincidently energizing selected combinations of said input windings, said elements beingr responsiveto the energization of said selected input windings to provide a net ux change in only the elements of Vone of said groups of elements; and a plurality of output windings, said outputwindings being dividedintoa plurality of sets, all the output windings in each of said sets coupling all the magnetic elements of y each of said groups of magnetic elements in accordance with an output combinational code, the sense in`which said output windings coupleV said magnetic elements being suchthat, for the energization of each selected combination of said input windings, the resulting net tluX changes in the elements of one of said groups of elements will induce a vnet voltage in only one of the output windings y coupling said group and cancelling voltages in all other i'output windings coupling the group.

2. A magnetic switch comprising a plurality of magnetic elements at least some of which are stable only at A ples only one element of each of said groups of elements in accordance with an input combinational code; means Again, if simultaneous Y outputs are desired or arev permitted on two or more outi2 for coincidently energizing selected combinations of said input windings, said elements being responsive to the energization of said selected input windings to provide a net flux change in only the elements of one of said` groups of elements; and a plurality of output windings, said output windings being divided into a plurality of sets, each of said sets having m. output windings, all the output windings in each of said setspcoupling all the magnetic elements of each of said groups of magnetic elements in accordance with an output combinational code, said output combinational code for each group of output windings being developed by expanding a matrix having the pattern into a m power matrix, the sense'in which said output windings couple said magnetic elements being such that, for the energization of each selected combination of said input windings, the resulting net ilux changes in the elementsof one of said groups of elements will in- "pledrby the desired output line will have net llux changes duce a net voltage in only one of the output windings coupling said group Vand cancelling voltages in all other output windings coupling the group.

3. A magnetic switch comprising a plurality of magnetic elements at least some of which are stable only at a near zero remanent induction level, said elements being 4arranged in groups of at least two elements each; a plurality of input windings, each of which couples elements of more than one group and couples only one element of each of said groups of elements in accordance with an input combinational code,j said input windings being di-- vided into a plurality of sets, all the inputl windings in each of said sets coupling one magnetic element from l'each of said groups of magnetic elements in accordance Vwith said input combinational code, said input combinational code being such that half the inputwindings coupling each magnetic element couple said each magnetic Velement ina irstmagnetizing sense and the other half of said input windings couplesaid each magnetic element Vin a second magnetizing sense; means for coincidentally oneof said groups of elements being coupled by at least one'of said output vwindings in accordance with an output combinational code, the sense in which saidoutput windings couple said magnetic elements being such that, for

the energization of each selected combination of said input` windings, the resulting net flux changes. in the elements of one of said groups of elements will induce a net voltage in only one ot the output windings coupling said group and cancelling voltages in all. other output windings couplingthe group.

4,. A magnetic switch comprising a plurality of magv netic elements at least some of which are stable only at windings being divided into a plurality of sets, where the number of input windings in each set of input windings is equal to 2nI Vall the inputwindings in each of said sets couplingonemagnetic element from each of said groups of magnetic elements in accordance Ywith said input combinational code, said input combinational Vcode for each a matrix having the pattern into an n power matrix with the pattern so formed being used for half the input windings and the complement of that pattern for the other half; means for coincidentally energizing selected combinations of said input windings, said elements being responsive to the energization of said selected input windings to provide a net ilux change in only the elements of one of said groups of elements; and a plurality of output windings, all the elements from each one of said groups of elements being coupled by at least one of said output windings in accordance with an output combinational code, the sense in which said individual output windings couple said magnetic elements being such that, for the energization of each selected combination of said input windings, the resulting net flux changes in the elements of one of said groups of elements will induce a net voltage in only one of the output windings coupling said group and cancelling voltages in all other output windings coupling the group.

5. A magnetic switch comprising a plurality of magnetic elements at least some of which are stable only at a near zero remanent induction level, said elements being arranged in groups of at least two elements each, there being 12X-l groups of magnetic elements, where x is a positive integer; a plurality of input windings, each of which couples elements of more than one group and couples only one element of each of said groups of elements in accordance with an input combinational code, said input windings being divided into a plurality of sets, each said set of input windings having 2X windings, all the input windings in each of said sets coupling one magnetic element from each of said groups of magnetic elements in accordance with an input combinational code such that half the input windings coupling each magnetic element couple it in a iirst magnetizing sense and the other half of said input winding couple said magnetic element in a second magnetizing sense, said input combinational code for each group of input windings being developed by starting with a basic pattern forming two columns of the next higher order pattern by use of the matrix expansion lII column basic pattern II column basic pattern basic pattern l complement of basic pattern adding ones and zeroes to the respective ends of the basic pattern until the total number of digits in the column equals that in the two new columns, using this newly formed pattern as the first column of the next higher order winding pattern, and following this method until the number of digits in each column equals 2x, each column of the preceding order pattern being used in place of the basic pattern in the above matrix to form two succeeding columns of the next higher order pattern; means for coincidently energizing selected combinations of said input windings, said elements being responsive to the energization of said selected input windings to provide a net flux change in only the elements of one of said groups of elements; and a plurality of output windings, all the elements from each one of said groups of elements being coupled by at least one of said output windings in accordance with an output combinational code, the sense in which said output windings couple said magnetic elements ybeing such that, Ifor the energization of each selected combination of said input'windings, the resulting net tlux changes in the elements of one of said groups of elements will induce a net voltage in only one of the output windings coupling said group and cancelling voltages in all other output windings coupling the group.

6. A magnetic switch comprising a plurality of magnetic elements at least some of which are stable only at a near zero remanent induction level, said elements being arranged in groups of at least two elements each; a plurality of input windings, each of which couples elements of more than one group and couples only one element of each of said groups of elements in accordance with an input combinational code, said input windings being divided into a plurality of sets, said number of sets of input windings being equal to (p-i-l) where p is a prime number and (p-t-l) is equal to a multiple of four, the number of said groups of magnetic elements being equal to p, all the input windings in each of said sets coupling one magnetic element from each of said groups of magnetic elements in accordance with said input combinational code, said input combinational code being such that halt the input windings coupling each magnetic element couple it in a rst magnetizing sense and the other half of said input windings couple said magnetic element in a second magnctizing sense, said input combinational code being the one which is arrived at when (l) the quadratic residues of numbers from 0 to (1J-1) are formed, (2) the sequence a0, a1, a2, a3 ap 1 is laid out in a column and a one inserted for a0 wherever the subscribe equals a quadratic residue and a zero in all other places, (3) the sequence obtained in step 2 is cyclically shifted to obtain a p by p matrix and (4) a row of Os is added .at the end of the matrix obtained in step 3; means for coincidentally energizing selected combinations of said input windings, said elements being responsive to the energization of said selected input windings to provide a net iiux change in only the elements of one of said groups of elements; and a plurality of output windings, all the elements from each one of said groups of elements being coupled by at least one of said output windings in accordance with an output combinational code, the sence in which said individual output windings couple said magnetic elements being such that, for the energization of each selected combination of said input windings, the resulting net ilux changes in the elements of one of said groups of elements will induce a net voltage in only one of the output windings coupling said group and cancelling voltages in all other output windings coupling the group.

7. A magnetic switch comprising a plurality of magnetic elements at least some of which are capable of producing in an associated winding an output voltageof either of two opposite polarities, said magnetic elements being grouped in a plurality of rows, a plurality of input windings coupled to said elements in accordance with an input combinational code, the sense of coupling of half the input windings with any element being opposite to the sense of coupling of the other half of the windings with the same element, means for coincidently exciting selected combinations of said input windings, each said selected combination having all of the windings coupled to one element from each row coupled thereto in the same sense, the windings of each selected combination having, on the other elements to which they are coupled, as many couplings of one sense as of the other sense whereby coincident excitation of a selected combination is effective to magnetically excite only a single selected element from each row of elements, a plurality of output windings coupled to said elements, at least some of said output windings being coupled to one element from each row, at least some of said elements having as many output windings coupled thereto as there are rows of elements, the sense of couplings of the several output windings with the several elements being such thatupon excitation of one element from each row only one output winding has induced therein voltages of aiding polar- 5 ity and all other output windings coupled to the excited elements will have induced therein as many voltages of one polarity as the other polarity.

References Cited in the ie of this patent UNITED STATES PATENTS Rajchman Feb. 7, 1956 Rajchman l Feb. 7, 1956 Rajchman Oct. 26, 1956 King et al. Dec. 13, 1960 Newby Feb. 28, 1961 

5. A MAGNETIC SWITCH COMPRISING A PLURALITY OF MAGNETIC ELEMENTS AT LEAST SOME OF WHICH ARE STABLE ONLY AT A NEAR ZERO REMANENT INDUCTION LEVEL, SAID ELEMENTS BEING ARRANGED IN GROUPS OF AT LEAST TWO ELEMENTS EACH, THERE BEING 2X-1 GROUPS OF MAGNETIC ELEMENTS, WHERE X IS A POSITIVE INTEGER; A PLURALITY OF INPUT WINDINGS, EACH OF WHICH COUPLES ELEMENTS OF MORE THAN ONE GROUP AND COUPLES ONLY ONE ELEMENT OF EACH OF SAID GROUPS OF ELEMENTS IN ACCORDANCE WITH AN INPUT COMBINATIONAL CODE, SAID INPUT WINDINGS BEING DIVIDED INTO A PLURALITY OF SETS, EACH SAID SET OF INPUT WINDINGS HAVING 2X WINDINGS, ALL THE INPUT WINDINGS IN EACH OF SAID SETS COUPLING ONE MAGNETIC ELEMENT FROM EACH OF SAID GROUPS OF MAGNETIC ELEMENTS IN ACCORDANCE WITH AN INPUT COMBINATIONAL CODE SUCH THAT HALF THE INPUT WINDINGS COUPLING EACH MAGNETIC ELEMENT COUPLE IT IN A FIRST MAGNETIZING SENSE AND THE OTHER HALF OF SAID INPUT WINDING COUPLE SAID MAGNETIC ELEMENT IN A SECOND MAGNETIZING SENSE, SAID INPUT COMBINATIONAL CODE FOR EACH GROUP OF INPUT WINDINGS BEING DEVELOPED BY STARTING WITH A BASIC PATTERN 